If, like me, you've worked on quite a few old cars, you would probably have noticed that the plastic sheet which VW and Audi so meticulously apply to the inside of door panels is either hanging in shreds or has disappeared altogether.
The culprits are most likely panel beaters, car radio installers or mechanics who have had to fix a rattle or a tight window; doing the job from their point of view does not extend to mucking around with plastic and glue, and the customer doesn’t notice anyway. Owners/workers are probably just as much to blame, though lack of proper materials and ignorance of what the sheeting is for are what probably guides them.
What are the. consequences of not properly sealing the door cavity? Rain water, which is able to get past even brand new window seals, will go straight onto the door trim. Which being made of flimsy pressed fibre board will buckle, tear and generally flop about. This same water can also leak through the door and inside the car onto the floor, where it sits for years underneath carpet and sound deadener promoting the dreaded iron oxide-
If the car has had speakers installed in the door skin (as mentioned above, a prime reason for the seal having been broken in the first place) water will go straight onto the membrane, which, usually being made, of thin cardboard will beat itself to slush. Reasons enough to do something about it?
The factory hasn't helped very much with their design. Unfortunately. Some other makers use a neat and durable plastic moulding which reinstalls without glue. The glue which VW/Audi uses works very well, so well that it is easy to rip the plastic when attempting removal. After that it doesn't stick again. So the conscientious person would need to have at hand the following sturdy plastic sheeting, which is expensive stuff and not normally lying around paint on contact adhesive and brush; scissors, knife and about half an hour per door. Now perhaps its hardly surprising that this job rarely gets done.
The point of this article, apart from making me feel better for directing a diatribe against shoddy
workmanship, is that there is a slightly easier short cut to reinstalling tile plastic sheeting. The hardest thing is with the glue contact adhesive is expensive and goes off in the pot, can't be re-used, is hard to apply and hard to clean up, smells bad, needs lots of time to cure and the solvent depletes the ozone layer- In fact it probably causes male impotence too. and I don't particularly like the colour.
What is needed is some environmentally friendly substance which sticks like the proverbial to a blanket again and again, has a long shelf life, is easily and quickly applied and removed, has no smell and doesn't cause reduced sperm count. Also. it must be a nice blues. This wonder stuff does in fact exist and is called "Blu-Tack". You know. the stuff you use to put Audi Sport and VW Nationals posters up on your bedroom wall.
You can roll it up in your hands into long snake and push it into place exactly where its needed. Be especially generous with it at the bottom of the door aperture, as this is where water tends to run into the gap between the door skin and the panel and go on to do its dirty work. Next time you remove the door trim and plastic sheet just roll the Blu Tack up again into another snake and re-apply when necessary. It's even recyclable!
Now lets say your putting speakers into your door trim, or re-applying the plastic sheet and speakers are going to go back on with the door trim. The magnet will push right through the sheet, right? So you'll have to cut a hole around space which the speaker occupies, thus defeating the whole purpose. My solution; get out your Bosch heat gun, which has hundreds of uses apart from burning off paint. Briefly heat up the plastic behind the speaker without letting it melt through, then push it with your fist to stretch it. You might need to do this a few times so that the correct clearance is created and will definitely burn your hand, but it's better than the. alternative, isn't it'? Then poke a small hole in the bottom of the indentation you have created, feed the speaker wire through and let it hang out.
An observation if you can afford German Blaupunkt speakers, you would have noticed that they have a protective covering preventing water from above from impinging onto the membrane. Also, Bose. an expensive US. brand, and probably others, have a waterproof membrane.
It really would be nice to find a car that somebody had treated with the above procedure. If you ever do it, please write this plastic was put on by ……. and your name so that in future, will know how far sighted you were.
Thanks to John Frizza for the "Blu-Tack" idea.
Rod Young
Note: From 16th August 1965, Chassis No. 116 073 288, a plastic sheet was cemented to the door Inner panel to provide better sealing against the entry of water between the door inner panel and the door trim panel. The plastic foam seal in the door trim panel has been discontinued. The plastic sheet is now obtainable under part number 111 867 147 B.
The rubber seals for the clips must be pressed Into the holes in the door inner panel after attaching the plastic sheet.
Important Only universal adhesive D 12 guarantees a good attachment of plastic sheet to door inner panel.